Circular micrometer



MMaur.. 13, 1923.

`. c.' F'. JoHNsroN r-:T AL

CIRCULAR MICROMETER Filed May 11, 1922 W7 mw between the anvil 22 andthe edge L23 drawing together the finger members 13 and 14 as forexample the width of the ring 24 between the faces 22 and 23. Thegraduations at 21'read on the vernier'scale 16 and give the exact ringwidths. Other finger members as 15 may be established at intervals, soas to make the drawing together of the movable slide by its fingerengaging end 13 for different diameters.

It is to be understood that the piston ring joint is to be tightly drawntogether to establish the true ringdiameter.

In making measurements of circles within the loop itis to be understoodthat the circular diameter is to bear against the ribbon which in turnbears against the track 2 at-the point 30; and again against the fulcrumpoint 7,A thus making two points of contact for the circular periphery.The ring 13 shown in full lines in Fig. 1 is not yet fully drawn up, thejoint 2O not being closed, and when so fully drawn up will occupy theposition of the dotted lines 31. The lower portion of the base plate 1we prefer to cut I throughl as on the line 32 so as to permit circularpieces of maximum size' to pass-l clearly through the said opening. Aslide plate 33 is provided and is inserted in suitable grooves as34bringing the base'plate surface" Hush under the measuring loop at timeswhen the device isemployed for measuring thin discsl or piston rings,the saidslide 33 being withdrawn, however, as by the finger engagingportion 35 when it is de'siredto measure a piston or other cylindricalobject having considerable length and which may then pass freely throughthe opening 32 in the said plate.

While we have shown but one form of our device, it will be understoodthat it may be i readily built in other forms and the invention embodiedin other structures and we desire to beunderstood as claiming suchvarithe track. y

track and slide thereon, a 'flexible inexten- 4 ifi/M5222 sible ribbonhaving one of its ends fixed to said slide and a body portion forming aloop to embrace an article to be measured and its other end fixed withrelation to said track during movement of said slide, a finger member onthe slide and another finger member fixed with relation to the trackwhereby the slide may be moved on the track and the said ribbon therebycaused to embrace said article, a scale on which the inovement of theslide is readable, and a base in fixed relation with said track havingan opening therethrough adjacent said loop adapted to permit objects tobe positionedv ysaid slide and a body portion forming a loop to embracean article to be measured and its other end Fixed-with relationy toksaid track during movement of said slide and means adapted to adjustvthe position of the slide with reference to the fixture of the ribbonand the track.

3. A circular micrometer, comprising a track and slide thereon, aflexible inextensible ribbon having one of its ends fixed to said slideand a body portion forming a loop to embrace an article to be measuredand its other end fixed with relation to said track during 'movement ofsaid slide, a iinger member on the slide and another finger member fixedwith relation to thetrack wing therethrough adjacent said loop adaptedvto permit objects to be positioned through the loop and the base, andmeans adapted to adjust the position of the slide with reference to thefixture of the ribbon and ciments r. Joiiivsroiv. Liiovn A. MAiiriNnLLi.

